Air conditioning system



Sept. 6,1938. M. K. DREWRY 2,129,202

' AIR CONDITIONING SYSTEM Filed Sept. 18, 19:53

.zz wmmlamw Patented Sept. 6, 1938 UNITED STATES PATENT OFFICE AIR CONDITIONING SYSTEM Montrose K. Drewry, Milwaukee, Wis. Application September 18, 1933, Serial No. 689,935

15 Claims.

This invention relates in general to air conditioning systems and particularly to apparatus for conditioning air and circulating it through enclosed spaces.

An object of the invention is to provide a simple and eflieient air conditioning apparatus for regulating the temperature and humidity conditions of the air in a building.

Another object of the invention is to provide an air conditioning'system that is arranged to operate efliciently and with minimum attention.

Another object of the invention is to provide an air conditioning system having means for automatically regulating the rate of combustion of fuel and the rate of circulation of air in accordance with conditions in the space being served with conditioned air;

A further object of the invention is to provide a new method of operating a heat exchange system in which, while the system is used for cooling purposes, the boiler is operated to heat storage water and is at all times prepared to take on a heating load.

According to the present invention, air conditioning apparatus having an air circulating system is provided with an air cleaner, a humidifier and a heat exchanger adapted to heat or cool the air as conditions may require. For heating the air, a boiler provided with an automatic fuel feeding hopper is connected to the heat exchanger, and automatic means are provided for regulating the rate of combustion of fuel I in the boiler and the rate of circulation of air in the circulating system in accordance with temperature conditions in the spacebeing heated. Flue gases are drawn through the fuel in the hopper to condition it for feeding by gravity and to improve its qualities for combustion. In warm weather, cold water is circulated through the heat exchanger to cool the air and to condense excess moisture out of it. coincidentally,

the boiler may be utilized for heating service water.

The foregoing and other objects of the invention may be achieved by the air conditioning system described by way of example in the following part of this specification in conjunction with the accompanying drawing, in which the single figure is a view, partly in side elevation and partly in vertical section, of apparatus embodying the invention installed in the basement of a building.

The illustrated air conditioning apparatus coupriseS, in general, an air circulating system including a conditioning chamber or cabinet I of rectangular shape associated with a heating furnace or boiler 2. The air conditioning apparatus is preferably located in the basement of the building to be served and the conditioning chamber I may be supported conveniently from the basement ceiling, as shown. Air to be conditioned is drawn from the rooms of the building being served into one or more intake registers 3 and through associated intake pipes or ducts! into the conditioning chamber I.

A partition 5, disposed in a vertical medial plane of the chamber 1 and extending from the top downward to near the bottom thereof, divides the chamber into an intake compartment 6, to the top of which the intake pipes 4 are connected, and a discharge compartment I. The partition 5 constrains the flow of the incoming air and directs it downward through a filter 8 arranged horizontally in the intake compartment 6 in position to remove dust and other foreign particles from the air. From the filter, the air flows downward to the bottom of the compartment 5 and thence horizontally through a connecting passageway beneath the lower end of the partition 5 into the compartment 1.

Atthe bottom of the compartment 1, there is arranged a humidifying tank or pan 9 that presents a surface of warm water to the infiowing filtered air from which the air absorbs a predetermined amount of moisture.

Above the humidifier 9, there is arranged a heat exchanging radiator ID that functions to heat or cool the air, according to the requirements of weather conditions, as it flows upward in the compartment 1. From the top of the compartment I, the air flows into outlet pipes ll through which it is delivered to one or more discharge registers It. in the rooms of the building being served, the air circulating system functioning, in general, in much the same manner as the circulating system of the usual warm air furnace.

The heat exchanger I is of the fin-ahd-tube type, having an inlet manifold or header l3 which is connected by an inlet pipe I to the upper part of the boiler 2 and from which a bank of finned tubes l extends horizontally across the compartment 1 to a return header l6. From the return header IS, a second bank of finned tubes II extends across the compartment beneath the tubes l5 to a discharge header l8 which is connected by a return pipe l9 to the lower part of the boiler 2. The tubes l5 and II are so spaced and positioned that the air, in flowing upward through the heat exchanger,

first passes between the tubes I! of the lower bank and then passes between the tubes ii of the upper bank.

As shown in the drawing, the heat exchanger I0 is arranged substantially at the level of the top of the boiler 2 to facilitate the circulation of hot water from the boiler through the water circulating system. In cold weather, when the system is being used for heating the building,

hot water from the top of the boiler 2 flows hori-' zontally through the inlet pipe l4 into and through the upper tubes l5 and then back through the lower tubes l! of the heat exchanger I 0 in series relation, giving up a. portion of its heat to the air in the compartment I. The water then flows from the heat exchanger into the vertically arranged return pipe I! and thence back to the bottom of the boiler.

As the column of relatively cool water in the vertical return pipe I9 is heavier than the corresponding column of hot water in the boiler, it descends by gravity, causing circulation by natural convection or thermo-syphon action through the heat exchanger. Because the heat exchanger is positioned substantially level with the top of the boiler, the column of cool water in the return pipe I 9 is of. suflicient height to cause effective thermo-syphon action in the system.

The air in the circulating system likewise is caused to circulate by thermo-syphon action, the heated air inthe compartment 1 rising into the outlet pipes H and being replaced by cool air from the compartment 6. To effect circulation of the air by thermo syphon action it is desirable that the heat exchanger be placed as low as.

possible in the air circulating system in order that the column of heated air may be of sufficient height to establish a difference in weight between it and the corresponding column of cold air great enough to provide pressure for effective circulation. By positioning the heat exchanger at the level of the boiler top, the conditions necessary for thermo-syphon circulation of both the water and the air are met in manner to effect equally satisfactory circulation of each.

The boiler 2 is provided at its top with an expansion tank or chamber 20 that serves as a storage reservoir for water which may be forced out of the boiler when the water therein is expanded by heat. The tank 20, being open to the atmosphere, also permits the escape of air or steamthat might otherwise interfere with the circulation of the water through the system, should the pipe i4 become air-bound or steamgound by reason of becoming filled with either uid.

An adequate supply of water is automatically maintained in the boiler at all times by means of an inlet valve 2! that controls the inflow of water from a supply pipe 22 to make up for water lost by evaporation or otherwise. The valve 2| is actuated automatically by a float 23 resting on the surface of the water in the expansion tank. The float 23 covers substantially all of the surface of the water in the tank and greatly reduces the absorption of air by the water when it cools below its boiling temperature, thereby avoiding corrosion of the interior of the water circulating system apparatus by air dissolved in the water.

Fuel for combustion in the firebox of the boiler 2' is fed into the firebox automatically by gravity from an air-tight fuel hopper 24 mounted on one side of the boiler. The hopper 24 may be filled periodically with solid fuel such as coal or coke through an opening 25 in .ts top which is normally closed by a close-fitting removable cover 26. The flue gases resulting from combustion of the fuel are conducted from the firebox by a smoke-pipe 21 that discharges into a chimney 28.

A relatively small pipe 29 is connected between the smoke-pipe 21 and the upper part of the fuel hopper 24 for conducting flue gases from the smoke-pipe into the top of the hopper to be drawn downward through the fuel by the natural draft of the firebox to condition the fuel for feed-' ing and burning. The fiue gases passing through the hopper, together with heat conducted from the boiler to the hopper, act upon the fuel therein in such manner that water vapor and certain gases are driven off and the fuel is otherwise so modified as to prevent burning or clogging thereof in the hopper or caking upon flowing from the hopper into the firebox. The conditioned fuel flows into the firebox by gravity continually and automatically at the rate at which it is required to replace the fuel consumed, thus maintaining a uniform bed of burning fuel on the firebox grate at all times.

An opening 30 is provided in the side of the firebox above the level of the fuel bed therein for introducing auxiliary air into the combustion chamber. To control theamount of auxiliary air introduced, the opening is provided with an adjustable cover 3|. The opening 30 may be utilized for starting the fire when the hopper contains a supply of fuel, as kindling materials may be inserted through it into the firebox and The rate of combustion of fuel in the firebox and the rate of heating resulting therefrom is regulated by a thermostat 32 so located as to be responsive to the temperature of the air in the rooms being heated and arranged to be regulated to maintain the air in the rooms at a predetermined desired temperature. The thermostat 32 is connected to a thermostat motor 33 in such manner as to energize it in response to changes in the room temperature. The thermostat motor 33 is connected, by a continuous chain carried by pulleys 35, to operate a. draft door 36 arranged to control the admission of air into the firebox beneath the bed of fuel therein, and to operate a check door 31 arranged to control the admission of air into the base of the chimney 28 for checking the fire.

When the temperature of the air in the rooms being heated falls below the predetermined desired temperature for which the thermostat is set, the thermostat and its associated motor function to close the chimney check door 31 and to open the draft door 36, thereby increasing the draft through the firebox and increasing the rate of combustion of fuel to furnish additional heat to the boiler water.

The boiler is provided with a water temperature regulator 38 that includes a thermoexpansion element 39 disposed in contact with the water in the boiler and connected by a link 40 to a pivoted lever arm 4i on which is slidably mounted an adjustable counterpoise weight 42. As the temperature of the boiler water increases in response to the action of the thermostat 32, the thermal expansion element 39 expands and pivots the lever arm 4!, lifting the weight 42. When the water temperature reaches a predetermined value, the lever arm 4| is pivoted to erably of the mercury type, mounted on the lever arm 4| closes and completes an electric circuit that leads from a power line 44 through conductors 45 to a motor 46 connected to a fan 41 dis- 5 posed in the lower part of the intake compartment 8. The fan is so directed as to increase the circulation of air through the system by forcing air from the intake compartment 6 into the discharge compartment 1 and upward through the 10 heat exchanger iii. The increased circulation of air through the heat exchanger results in conveying additional heat from the hot water circu lating through it and consequently tends to reduce the temperature of the water in the boiler. The additional heat transferred from the boiler water is conveyed by the air to the rooms being heated and raises the room temperature in response to the functioning of the thermostat 32.

When the predetermined normal temperature in the rooms is restored, the thermostat 32 actuates the thermostat motor 33 to cause it to close the draft door 36 and to open the check door 31,

thereby decreasing the rate of combustion of fuel in the firebox and reducing the amount of heat supplied to the boiler.

When the temperature of the water in the boiler becomes reduced below a predetermined value, as a result of the action of the fan and of the reduced rate of combustion of fuel cffected by the thermostat, the thermal expansion element 39 contracts and permits the weight 42 to pivot the lever arm 4| in such manner as to open the switch 43 and stop the fan motor 46,

thereby reducing the amount of heat supplied to the rooms and preventing the room temperature from exceeding the predetermined maximum.

If the predetermined normal temperature in the rooms is not restored within a short time, the temperature of the boiler water will continue to increase while the fan 41 is operating in spite of the cooling eifect of the fan, and the water temperature regulator 38 will function, through a connection with the draft and check doors, to reduce the rate of fuel combustion and 45 prevent overheating of the boiler water. This action of the water temperature regulator will occur regardless of the fact that the thermostat motor 33 may be tending, at the time, to increase the rate of fuel combustion.

To enable this result to be accomplished, the continuous chain 34 of the draft regulating mechanism is connected to the draft door and to the check door by means of pulleys 48, one of which ismounted on each door, the pulleys being arranged to rotatably receive the chain. The runof the chain at the sides of the pulleys 48 .opposite from the run thereof that is connected to the thermostat motor 33, is attached to the end of the lever arm 4|, as shown. When'the.

temperature of the boiler water exceeds a predetermined maximum, .the lever arm 4| of the temperature regulator 38 is moved to the position shown in the drawing and in so doing actuates the chain 34 to close the draft door 36 and 5 to open the check door 31 independently of the action of the thermostat motor '33. As the thermal expansion element 39 which operates the arm 4| expands or contracts in accordance with temperature changes of the water in the boiler,

70 its action causes the temperature regulator 38 to actuate the draft door and the check door in modulating manner to maintain the temperature of the boiler water substantially constant. This arrangement prevents overheating of the boiler 5 water and prevents the formation of excess steam which would otherwise interfere with the circulation of the water through the heat exchanger III by steam-binding the pipe l4.

The water temperature which the regulator 38 will tend to maintain in the boiler and the temperature at which the fan motor will be started or stopped, may be regulated by adjusting the position of the weight 42 along the lever arm 4|. An incidental effect of this adjustment is to regulate the amount of time during which the fan 41 will operate under given conditions. For example, if the weight 42 is set to maintain relatively high water temperature the fan will not operate as much of the time as it will in delivering an equal amount of heat when the weight 42 is set to maintain relatively low water temperature.

The smoke-pipe 21 is made air-tight in order that the flue gases it conducts to the chimney 28 may surrender the maximum amount of heat to the basement air and thus decrease fuel costs. Ordinarily, in the usual furnace installation a. check door is located in the smoke-pipe near the boiler, but the air it admits at this location so cools the flue gases passing through the, smokepipe that most of the flue gas heat is wasted by escaping up the chimney. Also, deterioration of the smoke-pipe is ordinarily more rapid when air is admitted to it than is the case with the airtight design illustrated in the drawing.

For heating service water, an indirect water heater 49 is connected in a minor circulating system paralleling the main circulating system through the heat exchanger. This minor circulating system includes a pipe 58 leading from the pipe M at the top of the boiler to the heater 49, and a pipe 5| leading from the heater to the return pipe l9 near the bottom of the boiler. The service water circulates from the bottom of a hot water storage tank-.52, through a pipe 53 upward into and through a heating coil in the heater 49 and thence through a pipe 54 into the top of the storage tank. Water is supplied to the bottom of the hot water storage tank 52 through a pipe 55 that is connected to the supply pipe 22, and hot water is delivered from the top of the tank through a pipe 88 that leads to the various positions throughout the buildingatwhich the hot water is utilized.

Circulation of water from the boiler through thetheater 48 occurs because of the fact that the temperature of the water is lowered in imparting heat to the service water in the heating coil.

Consequently, the column of water in the vertical return pipe 5| is cooler and denser than a corresponding column of water in the boiler, and the cool water column descends through the pipe 5| by gravity, causing circulation by natural convection.

The circulating water in the pipe 5| is utilized to provide heat for evaporating the water in the humidifying tank 9. As shown, the humidifier is provided with a submerged heating coil 56 into which water may flow from the pipe 5| through a pipe 51 and from which it flows through a pipe 58 to the return pipe l8. The flow of water through the heating coil 55 may be regulated by a valve 59 in the pipe 51 and a valve 68 arranged to close the portion of the pipe 5| between the pipe 51 and the pipe l9. By manipulating these valves, the temperature of the water in the humidifier may be controlled, thus regulating the rate of evaporation of the water and the humidiflcation of the air circulating through the conditioning chamber. As

a further means of controlling the action of the a humidifier, the amount of water surface exposed to the air may be regulated by covering a portion of the tank 9.

The level of the water in the humidifying tank 3 is maintained substantially constant by a floatoperated valve 6! which automatically admits water from a pipe 62 that is connected to the supply pipe 22 to replenish water evaporated in humidifying the air. To prevent corrosion of the humidifier or the formation of scale therein, chemicals of the nature ordinarily utilized in steam boilers for such purposes may be added to the water. 1

In front of the fan 41 and over the humidifying tank 9, there is arranged a series of directing vanes 63 that turn the circulating air uniformly upward into the heat exchanger ill with minimum loss of energy. 6

Auxiliary air may be introduced into the circulating system through an auxiliary air intake pipe 64 extending from the intake compartment 6 out of doors for admitting fresh outside air and having a damper 65 for controlling the volume of air admitted. A second auxiliary air intake pipe '66 opening into the basement is connected to the compartment 6 and is likewise provided with a damper 61 for controlling the volume of air admitted from the basement into the system.

During warm weather the air conditioning. system is utilized for cooling and drying the air in the building. To adjust the system for this mode of operation, a valve 68 in the pipe l4 and a valve 69 in the pipe I9 are closed to isolate the heat exchanger ID from the boiler, leaving the minor,

circulating system through the service water' heater 49 connected to the boiler. Cold water from the supply pipe 22 is then admitted to the heat exchanger through a pipe 10 having a control valve II which leads into the pipe I4. From the pipe l4 the water flows through the upper bank of tubes l5 of the heat exchanger to the header l6 and then back through the lower bank of tubes I'I into the header is and the return pipe I 9 from which it escapes through a discharge valve 12 into a discharge pipe 13. 'Ordinarily, the water discharged through the pipe 13 is put to some useful Purpose, as for supplying a fountain and pool or for watering the lawn or garden, such use being suggested by a faucet 14 which is provided at the end of pipe 13 that extends out of doors for attaching 'a hose. Refrigerated water or other- .cooling fluid may be circulated through the heat exchanger instead of water from the usual city pply.

For circulating the air through the circulating system while the cold water is passing through the heat exchanger, the fan motor 46 is operated to drive the fan 41 continuously. To provide for selectively operating the fan motor 46, a manually operated push-button switch I6 is arranged to connect the conductors 45 which lead to the motor directly to the power line 44. Another pushbutton switch 16 is arranged in the circuit of the mercury switch 43 on the lever arm 4! and may be opened to render the mercury switch inoperative while the system is being used for cooling.

The fan 41 forces the air upward first through the spaces between the lower tubes l1 and then through the spaces between the upper tubes I! of the heat exchanger. In this manner the air first comes in contact with and is cooled by the tubes containing water that has been warmed somewhat, and then the partly cooled air passes over the tubes containing the cold water. This is in accordance with the counterfiow principle of heat transfer wherein the warmest air comes in contact with the warmest tubes and the coolest air passes over the coldest tubes, the arrangement which is generally recognized as the most eflicient for the transfer of heat between fluids.

Dining the period in which the apparatus is being used to cool the air, the supply of water to the humidifier 9 is interrupted by closing a valve I1 in the pipe 62, and the water is drained from the tank by opening a valve 18 in a drainpipe 19. When the warm air from the rooms comes in contact with the cold tubes of the heat exchanger, the excess water vapor in the air condenses upon the surface of the tubes, thus reducing the humidity of the air. The moisture which collects on the tubes drips into the humidifier tank 9 and is drained away through the adjustable weight 42 on the water temperature regulator 36 is then so positioned that the regulator 38 will operate to close the draft door 36 and open the check door 31 in opposition to the tendency of the thermostat when the desired service water temperature is attained. The regulator thus adjusted will maintain a low fire in the firebox to heat the service water to a predetermined temperature without further attention to the apparaus other than refilling the fuel hopper 24, which ordinarily is necessary only at weekly intervals. Should changing weather conditions, such as occur in the spring or in the fall, make it desirable to change the mode of operation of the apparatus from cooling to heating because of a sudden drop in temperature, it is merelynecessary to shut off the flow of cold water through the heat exchanger and reconnect it to the boiler by opening the valves 68 and 69. The hot water always available in the .boiler provides instant heating effect and the continuously burning fire can at once be placed under the control of the thermostat 32 to bring the air in the rooms to the desired temperature.

Although a specific air conditioning system has been described in detail herein for the purpose of clearly disclosing a practical embodiment of the invention, itis to be understood that the particular structure set forth is susceptible of modification without departing from the spirit and scope of the invention as defined by the subjolned claims.

It is claimed and desired to secure by Letters Patent:

1. An air conditioning system for serving a mutants spaces m e a conditioning chamber, a plurality of air intake pipes connected to said chamber for drawing air to be conditioned fromv said plurality of spaces being served, other air inlet pipes connected to said.

chamber for admitting air from other sources, means for controlling the amount of air admitted through said latter inlet pipes, an air filter ar-,

the humidifying action thereof, a heat exchanger said chamber by thermo-syphon action, a plurality of delivery pipes connected to said chamber for receiving and distributing the conditioned air to said plurality of spaces, a fan arranged in said chamber for assisting the circulation of air therethrough, and means operative in response to conditions in said spaces being air conditioned for controlling the operation of said fan.

2. An air conditioning system 4 for alternate heating and cooling of an enclosed space, comprising a boiler for heating water, a heat exchanger, means connecting said heat exchanger to said boiler in such manner as to permit fiow of hot water from said boiler through said heat exchanger by thenno-syphon action, an air condltioning chamber enclosing said heat exchanger, means for circulating air being conditioned through said chamber in contact with said heat exchanger and into the space being served to heat said space, means for automatically regulating said boiler in response to conditions in the space being served with conditioned air, a tank for storing warm service water, a service. water heater connected to be heated by said boiler and arranged to supply warm water to said service water tank, means for closing said heat exchanger connecting means'to isolate said heat exchanger from said boiler, means for circulating cooling fluid through said heat exchanger when isolated from said boiler to cool the space being served, and means for automatically regulating the fire in said boiler in response to the temperature of the water therein in manner tending to maintain the water temperature substantially con stant to heat service water automatically for storage in said service water tank while said heat exchanger is being utilized for cooling the conditioned air thereby keeping the fire active and instantly available for heating. the space being served upon opening the connecting means between said boiler and said heat exchanger.

3. A space heating system for automatic heating by the combustion of solid fuel, comprising a boiler for heating water and having a firebox for burning solid fuel provided with draft control dampers, a heat exchanging radiator connected to the top and the bottom of said boiler and disposed substantially at the level of the top of said boiler in position to facilitate thermosyphon circulation of water therethrough, an air conditioning chamber enclosing said heat exchanging radiator and arranged to facilitate thermo-syphon circulation of air through said radiator and into the space being heated, a fan disposed within 'said chamber and operative to accelerate the circulation of air through said heat exchanging radiator, means responsive to the temperature of the water in said boiler connected to cause said fan to operate when said water attains a predetermined temperature to accelerate' the transfer of heat to the space being heated and for so regulating the draft control dampers of said firebox as to tend to maintain the boiler water temperature uniform, means responsive to the temperature of the air in the space being heated and connected to superimpose its action upon that of the water temperature regulator to so regulate the draft control dampers of said firebox as to tend to maintain the temperature of said air constant, a fuel hopper disposed to automatically feed fuel by gravity into said firebox continuously to replace the fuel consumed therein and to maintain a uniform fuel bed, and means for conducting flue gases from said firebox through the fuel in said hopper to condition it for uniform automatic feeding into said firebox whereby completely automatic space heating by the combustion of solid fuel is effected.

4. A space heating system, comprising a boiler for heating water and having a firebox provided with draft control dampers, a heat exchanging radiator connected to the top and to the bottom of said boiler and disposed horizontally at the level of the top of said boiler in position to facilitate thermo-syphon circulation of water therethrough, an air conditioning chamber having a vertically disposed compartment enclosing said heat exchanging radiator and arranged to direct air upward therethrough, air pipes connecting said chamber to the space being heated and arranged to facilitate thermo-syphon circulation of air through said radiator and into said space being heated, a filter disposed in said chamber in position to filter the incoming air, a humidifying tank disposed in said chamber beneath said radiator to humidify the filtered air, a fan disposed in said chamber and operative to accelerate the circulation of air through said heat exchanging radiator, means responsive to the temperature of the water in said boiler connected to'cause said fan to operate when said water attains a predetermined temperature and connected to so regulate the draft control dampers of said firebox .as to tend to maintain the boiler water temperature uniform, and means responsive to the temperature of the air in the space being heated and connected to superimpose its, action upon that of the water temperature regulator to so regulate the draft control dampers of said firebox as to tend to maintain uniform temperature in said heated space.

5. An air conditioning system for conditioning air in a plurality of spaces, comprising a cabinet of substantially rectangular shape provided with a medially disposed dividing wall extending from the top thereof downwardly dividing the cabinet into an intake compartment and a discharge compartment with a connecting passageway along the bottom thereof, a plurality of inlet pipes connected to the top of said intake compartment for admitting air to be conditioned, a filter arranged in said intake compartment beneath said inlet pipes to filter said air, a fan disposed in said intake compartment beneath said filter and directed towards the connecting passageway for circulating air through said cabinet,

a humidifying pan disposed on the bottom of the discharge compartment in front of said fan in position to receive an air blast therefrom, means in said humidifying pan for heating water therein to humidify the air blown over the water by said fan, a heat exchanger disposed directly above said humidifying pan in said discharge compartment for heating said air, and a plurality of outlet pipes connected to the top of said discharge compartment for delivering the conditioned air to a plurality of spaces being served.

6. An air conditioning system for conditioning air in a plurality of spaces in a building, comprising a cabinet divided by a medial dividing wall into an intake compartment and a discharge compartment connected by a horizontal passage along the bottom thereof, a plurality of air inlet pipes connectedto the top of said intake compartment and communicating with the plurality of spaces being conditioned for drawing air therefrom, an auxiliary air inlet pipe connected to the top of said intake compartment and communicating with the exterior of the building for admitting outside air into the system, means for controlling said auxiliary air inlet to regulate the amount of outside air admitted into the system, an air filter arranged in said intake compartment beneath said inlet pipes in position to filter air drawn into said intake compartment, a fan disposed in said intake compartment beneath said filter and directed toward the horizontal passageway into the discharge compartment, a humidifying pan disposed in the bottom of said discharge compartment in position to receive a blast of air from said fan for humidifying said air, a heat exchanger disposed in said discharge compartment above said humidifying pan for heating said air, and a plurality of outlet pipes connected to the top of said discharge compartment and communicating with the plurality of spaces being conditioned for delivering conditioned air to said spaces. I

7. An air conditioning apparatus adapted for installation in the basement of a building for conditioning the air in other parts of the building, comprising an air conditioning cabinet having a medial dividing wall separating it into an intake compartment and a discharge compartment connected by a horizontal passage along the bottom thereof, an air inlet pipe connected to the top of said intake compartment and communicating with the part of the building. being served to withdraw air therefrom for conditioning said air, an auxiliary air inlet pipe connected to the top of sad intake compartment and communicating with the exterior of the building for admitting outside air into said cabinet, means for controlling the amount of outside air admitted through said auxiliary inlet pipe, an auxiliary air inlet opening in the top of said intake compartment for admitting basement air into said cabinet, means for controlling the amount of basement air admitted through said auxiliary opening, an

a air filter arranged in-said intake compartment d'sposed in the bottom of below said air inlets in position to filter the incoming air, a fan disposed beneath said filter to circulate air from said intake compartment into said discharge compartment, a humidiiying pan disposed in the bottom of said discharge compartment to'humidify-said circulating air, a heat exchanger disposed in said discharge compartment above said humidifying pan to heat said air, and an air outlet pipe connected to the top of said d'scharge compartment and communicatng with the parts of the building being served to deliver conditioned air thereto.

8. A heating system, comprising a'boiler for heating water, a heat exchanger cabinet associated with said boiler, a radiator disposed in said heat exchanger cabinet and connected to said boiler for transferring heat from said boiler to air in said heat exchanger, a humidifying pan said heat exchanger cabinet for evaporating water to humldify the air being heated. a heating coil in said humidifying pan for heating water therein, a circulating system connecting said humidifying pan heating coil with said boiler, and a connected in said circulating system near the top of said boiler and arranged to heat service water by transfer of heat from said boiler water, whereby circulation of boiler water through said humidifying Dan heating coil is effected by reason of the drop in temperature of said boiler water in said service water heating coil resulting in thermo-syphon action in said circulating system.

service water heating coil 9. A space heating system comprising a boiler for heating water by the combustion of fuel and said draft control means, a thermo-expansive temperature responsive means associated withsaid boiler and connected to-rock said lever in accordance with changesin temperature of said boiler water to actuate said draft control in manner tending to maintain the temperature of said boiler water substantially constant; means responsive to the temperature of the space being heated and arranged to change the connection between said lever and said draft control means upon the temperature of said space falling below a predetermined minimum value to cause said temperature responsive means to tend to maintain said boiler water at a higher temperature than is maintained when said space temperature is above said minimum value, means controlled by said pivoted lever for increasing the rate of delivery of heat to the space being heated upon said boiler water exceeding a predetermined temperature, and a weight slidingly mounted on said pivoted lever for adjusting the relation of said lever to said thermo-expansive means to regulate the temperature of said boiler water and the operation of said heat delivery increasing means.

10. In a space heating system for closely regulated heating by the combustion of solid fuel, the

combination with a boiler for heating water provided with a firebox for the combustion of solid fuel, of means for feeding solid fuel into said firebox uniformly by action of gravity, means for regulating means in modulating manner in accordance with changes in the water temperature and proportionately thereto, means for adiusting said water temperature responsive means to change its range of movement relative to the temperature of said boiler water, adjustable operating means connecting said water temperature responsive means to said draft regulating means to enable modulating operation of said draft regulating means in accordance with changes of boiler water temperature to control the rate of combustion in said firebox in manner tending to maintain said boiler water at a uniform temperature determined by the adjustment of said water temperature responsive means, and means responsive to the temperature of the air in the space being heated connected to said adjustable operating means in manner to change the relation of said water temperature responsive means to said draft regulating means to effect greater opening of said draft regulating means when the air temperature falls below a predetermined minimum tending to maintain said boiler water at a higher temperature than obtainswhen said air temperature is above said predetermined minimum, and means controlled by said watertemperature responsive means for increasing the rate of heat movement to said space being heated upon the temperature of said boiler water exceeding a predetermined maximum.

11. A space heating system comprising a boiler for heating water by the combustion of fuel, a heat exchange radiator associated with saidboiler, a water circulating system connecting said radiator to said boiler in manner to provide thermo-syphon circulation of boiler water through said radiator, an air circulating system enclosing said water temperature responsive means and said combustion control mechanism to cause said water temperature responsive means to actuate said combustion control mechanism in manner tending to maintain said boiler water at a higher temperature upon the space temperature falling below a predetermined minimum than is maintained when the space temperature is above said predetermined minimum to increase the rate of heating by said boiler, a fan disposed in said air circulating system in position to augment the circulation of air therethrough, and means actuated by said water temperature responsive means controlling the operation of said fan to cause it to operate when the temperature of said boiler water exceeds a predetermined maximum to increase the circulation of air through said radiator thereby increasing the rate of delivery of heat from said radiator to the space being heated and consequently increasing the rate of thermo-syphon circulation of water through said radiator to increase the rate at which heat is conveyed from said boiler to said radiator.

12. An air conditioning system for selectively heating or cooling an enclosed space, comprising a boiler for heating water, a heat exchanger ar ranged to serve said enclosed space, means connecting said heat exchanger to said boiler in manner to permit circulation of hot water from said boiler through said heat exchanger to heat .said space, means to close off said connecting means to isolate said boiler from said heat exchanger, a service water heating system associ-' ated with said boiler including a tank for storing heated service water and a water heater disposed to be heated by said boiler and connected to supply hot water to said storage tank, means ar- I ranged to circulate cooling fluid through said heat active operation while isolated from said heat ex changer and is therefore instantly available for quickly heating the space being served upon opening said closing off means to admit hot water from said boiler into said heat exchanger.

13. An air conditioning system for selectively heating or cooling an enclosed space, comprising a boiler for heating water, a heat exchanger arranged to serve said enclosed space, means connecting said heat exchanger to said boiler in manner to permit circulation of hot water from said boiler by natural convection through said heat exchanger to heat said space, manually operable means to close ofl said connecting means to isolate said boiler from said heat exchanger, a service water heating system associated with said boiler including a tank for storing heated service water and a water heater disposed to be heated by said boiler and connected to supply hot water to said storage tank, means arranged to circulate cooling iiuid through said'heat exchanger while it is isolated from said heat exchanger and istherefore instantly available for quickly heating the space being served upon opening said closing ofi means to admit hot water from said boiler into said heat exchanger.

14. The method of operating a heat exchange system which comprises circulating a-heat conducting medium through a boiler in circuit with a heat exchanger and a storage water heater during cold weather, and isolating the heat exchanger from the boiler and storage water heater in warm weather and passing a cooling fluid through the heat exchanger, and maintaining the boiler in operation to provide heat for the storage water heater and to provide reserve heat for the heat exchanger.

15. combination, a boiler, a hot water storage tank, a cabinet, a heat exchanger in said cabinet, a fan for forcing air through said cabinet, a

- source of cold water supply, adjustable means connecting said heat exchanger with said source, said boiler and said storage tank whereby air may be heated or cooled in said cabinet while the boiler remains in operation, and thermostatic means for automatically controlling said boiler for air heating requirements, said means also controlling the boiler for storage water heating while the cabinet is serving as a cooling means.

MONTROSE K. DREWRY. 

